3D printing advances end to animal testing with Harvard’s heart on a chip
Researchers at Harvard University have managed to 3D print a functional heart on a chip that could eradicate the need for animal testing in biomedical studies. Microphysiological systems (MPS) otherwise known as organs-on-chips, have been around for some time now and researchers continue to develop new techniques using them to replicate the function of organs. For example, in studies testing new medicines or cell cultures. What’s new with this research, and especially illuminating about the study published in Nature Materials just yesterday, is that The Wyss Institute for Biologically Inspired Engineering has managed to integrate sensors into the 3D printing process and also use 3D printing to make the manufacturing process, relatively, easier.
The key development in the fabrication process is the production of 6 new 3D printable inks, including one consisting of transparent thermoplastic polyurethane, and another made from dextran, a construct of molecules related to glucose.
Though the 3D printing process, seen in the video above, is simple in its execution, developing 3D printing technology to create such a chip has not been easy. Traditionally, a microphysiological system (MPS), or organ-on-a-chip, is created in complex steps using a multi step lithography process, which is not only expensive and slow, but does not integrate sensors into the process. As Johan U. Lind, co-author of the paper, explains:
Researchers are often left working in the dark when it comes to gradual changes that occur during cardiac tissue development and maturation because there has been a lack of easy, non-invasive ways to measure the tissue functional performance.
The heart on a chip has the ability to self-contract (see above), is able to mimic the electrophysiology (think defibrillators) of a human heart, and can also be manipulated to mimic a diseased organ. With the integral sensors, the team were able to measure the beating of the heart, record the development of cardiac tissues, and the response of the heart tissue to toxic substances.
In his statement on the research, Lind went on to add:
These integrated sensors allow researchers to continuously collect data while tissues mature and improve their contractility. Similarly, they will enable studies of gradual effects of chronic exposure to toxins.
An ability to make microphysiological systems quickly and with such ease, will in turn speed up the process of future discovery. This heart is the team’s most complex chip to date. Previous research by members of the group has used a similar process to create a lung-on-a-chip, and more recently the researchers shared the news that they had successfully 3D printed the micro-structure of a kidney. Jennifer Lewis, co-author of this new research, the paper Bio-printing of 3D Convoluted Renal Proximal Tubules on Perfusable Chips and senior Professor of Biologically Inspired Engineering, had the following to say about the heart on a chip:
We are pushing the boundaries of three-dimensional printing by developing and integrating multiple functional materials within printed devices. This study is a powerful demonstration of how our platform can be used to create fully functional, instrumented chips for drug screening and disease modeling.
The finished structure of 3D printed hearts on chips. Screenshot via: Harvard John A. Paulson School of Engineering and Applied Sciences on Youtube
3D printing or Additive manufacturing is a process of making a three-dimensional solid object of virtually any shape from a digital model. 3D printing is achieved using an additive process, where successive layers of material are laid down in different shapes. 3D printing is also considered distinct from traditional machining techniques, which mostly rely on the removal of material by methods such as cutting or drilling (subtractive processes).
A 3D printer is a limited type of industrial robot that is capable of carrying out an additive process under computer control.
While 3D printing technology has been around since the 1980s, it was not until the early 2010s that the printers became widely available commercially. The first working 3D printer was created in 1984 by Chuck Hull of 3D Systems Corp. Since the start of the 21st century there has been a large growth in the sales of these machines, and their price has dropped substantially. According to Wohlers Associates, a consultancy, the market for 3D printers and services was worth $2.2 billion worldwide in 2012, up 29% from 2011.[
The 3D printing technology is used for both prototyping and distributed manufacturing with applications in architecture, construction (AEC), industrial design, automotive, aerospace, military, engineering, civil engineering, dental and medical industries, biotech (human tissue replacement), fashion, footwear, jewelry, eyewear, education, geographic information systems, food, and many other fields. One study has found that open source 3D printing could become a mass market item because domestic 3D printers can offset their capital costs by enabling consumers to avoid costs associated with purchasing common household objects.
3D Printable Models
3D printable models may be created with a computer aided design package or via 3D scanner. The manual modeling process of preparing geometric data for 3D computer graphics is similar to plastic arts such as sculpting. 3D scanning is a process of analyzing and collecting data of real object; its shape and appearance and builds digital, three dimensional models.